[PlanetCCRMA] FC17 RT Performance

Fernando Lopez-Lezcano nando at ccrma.Stanford.EDU
Wed Jul 18 18:25:06 PDT 2012

On 07/18/2012 03:51 PM, John S. Dey wrote:
> Fernando,
> Well I am making progress.  In qjackctl settings--realtime button was checked.  The priority was set to default (I think).  Anyway--I set the priority to 66 and I am running 5.33ms (no xruns).  I haven't loaded the system to any degree yet but plan to soon.  A ps on jackd now shows: /usr/bin/jackd -P66 -dalsa -dhw:0 -r48000 -p128 -n2 -P.  I can't get rid of the trailing -P.  I cleared .jackdrc but it just reset to the same value on re-invocation of qjackrc.  How can I get rid of the trailing -P?

Hmmm, that is strange, priorities should be "perfectly" ordered by 
default so there's something going on that is not completely right. 
Could you send me the output of this while jack and a client are running?:

ps -eo pid,class,rtprio,ni,pri,pcpu,stat,comm --sort -rtprio

> With the testing I have been doing I have been using the stock sound card from Intel that came with the machine.
> I have been getting an error when starting qjackctl: "Could not open ALSA sequencer as a client.  Alsa MIDI patchbay will not be available."  I assume I'm missing an application.  Any idea what its called or if it not a missing application any ideas how to clean up the error?  Many thanks again for all you do.

This is a known bug. You can add a file named 
/etc/modprobe.d/snd-seq.conf that contains:

install snd-pcm /sbin/modprobe --ignore-install snd-pcm && 
/sbin/modprobe snd-seq

The module snd-seq should be autoloaded the next time you boot (or you 
can just manually do a "/sbin/modprobe snd-seq").

-- Fernando

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